Method and apparatus for dispatching a channel quality indicator feedback in multicarrier system

ABSTRACT

In accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with channel quality indicator (CQI) feedback in connection with one or more downlink carriers. An anchor carrier scheme is employed to provide channel quality indicator (CQI) feedback of one or more downlink carriers. An indication is set to identify that a designated uplink carrier is used to convey the CQI feedback. An uplink carrier is selected from a set of uplink carriers as an anchor carrier to convey the CQI feedback. CQI feedback is transmitted for one or more downlink carriers using the designated carrier.

CROSS-REFERENCE

This application is a divisional of U.S. application Ser. No.12/813,451, filed Jun. 10, 2010, entitled A METHOD AND APPARATUS FORDISPATCHING A CHANNEL QUALITY INDICATOR FEEDBACK IN MULTICARRIER SYSTEM,which claims the benefit of U.S. Provisional Application Ser. No.61/186,329, filed Jun. 11, 2009, entitled “CQI FEEDBACK FOR MULTICARRIERSYSTEM,” and assigned to the assignee hereof the entirety of which isincorporated herein by reference.

BACKGROUND

I. Field

The present disclosure pertain to wireless communication systems, and inparticular, to multicarrier system(s) that benefit from efficientmethod(s) of channel quality indicator (CQI) feedback.

Wireless communication systems are widely deployed to provide variouscommunication content such as for example: voice, video, packet data,messaging, broadcast, etc. These wireless systems may be multiple-accesssystems capable of supporting multiple users by sharing available systemresources. Examples of such multiple-access systems include CodeDivision Multiple Access (CDMA) systems, Time Division Multiple Access(TDMA) systems, Frequency Division Multiple Access (FDMA) systems,Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA)systems.

Generally, a wireless multiple-access communication system canconcurrently support communication for multiple wireless terminals. Eachterminal can communicate with one or more base stations viatransmissions on forward and reverse links The forward link (ordownlink) refers to the communication link from base stations toterminals, and the reverse link (or uplink) refers to the communicationlink from terminals to base stations. This communication link can beestablished for example via a single-in-single-out,multiple-in-signal-out or a multiple-in-multiple-out (MIMO) system.

A wireless system may support operation on multiple carriers. A carriermay refer to a range of frequencies used for communication and may beassociated with certain characteristics. For example, a carrier maycarry synchronization signals, or may be associated with systeminformation describing operation on the carrier, etc. A carrier may alsobe referred to as a channel, a frequency channel, etc. A base stationmay send data on one or more carriers on the downlink to user equipment(UE). The UE may send feedback information on the uplink to support datatransmission on the downlink It may be desirable to efficiently uplinkcarriers to send the feedback information to the base station.

SUMMARY

The following presents a simplified summary in order to provide a basicunderstanding of some aspects of the disclosed aspects. This summary isnot an extensive overview and is intended to neither identify key orcritical elements nor delineate the scope of such aspects. Its purposeis to present some concepts of the described features in a simplifiedform as a prelude to the more detailed description that is presentedlater.

In accordance with one or more aspects and corresponding disclosurethereof, various aspects are described in connection with channelquality indicator (CQI) feedback in connection with one or more downlinkcarriers.

It is to be appreciated that although various embodiments are describedherein with respect to channel quality indicator (CQI), it is to beappreciated that such embodiments are intended to include employment ofprecoding matrix index (PMI), rank indicator (RI), CQI, or a combinationthereof.

Furthermore, the term subset as employed herein is intended to cover therange of a portion of the set to all of the set.

In one aspect, an apparatus is employed in a wireless communicationusing a multicarrier system, the apparatus comprising: means for usingan anchor carrier scheme to provide channel quality indicator (CQI)feedback of one or more downlink carriers; means for selecting an uplinkcarrier from a set of uplink carriers as an anchor carrier to convey theCQI feedback; and means for transmitting the CQI feedback for one ormore downlink carriers using the designated carrier.

In another aspect, a method for use in a wireless communication using amulticarrier system, comprises: using an anchor carrier scheme toprovide channel quality indicator (CQI) feedback of one or more downlinkcarriers; setting an indication to identify that a designated uplinkcarrier is used to convey the CQI feedback; selecting an uplink carrierfrom a set of uplink carriers as an anchor carrier to convey the CQIfeedback; and transmitting the CQI feedback for one or more downlinkcarriers using the designated carrier.

In yet another aspect, an apparatus used in a wireless communicationusing a multicarrier system, comprises: at least one processorconfigured to use a anchor carrier scheme to provide channel qualityindicator (CQI) feedback of one or more downlink carriers, to set anindication to indicate that a designated uplink carrier is used toconvey the CQI feedback, to select a uplink carrier from a set of uplinkcarriers as an anchor carrier to convey the CQI feedback, and totransmit the CQI feedback for one or more downlink carriers using thedesignated carrier.

Another aspect provides for a computer program product, comprising: acomputer-readable medium comprising: code for using an anchor carrierscheme to provide a channel quality indicator (CQI) feedback of one ormore downlink carriers; code for setting an indication to indicate thata designated uplink carrier is used to convey the CQI feedback; code forselecting a uplink carrier from a set of uplink carriers as an anchorcarrier to convey the CQI feedback; and code for transmitting the CQIfeedback for one or more downlink carriers using the designated carrier.

In an aspect, an apparatus used in a wireless communication using amulticarrier system, comprises: means for determining if an asymmetricconfiguration is used, wherein a designated uplink carrier is employedto provide channel state information regarding one or more downlinkcarrier; and means for providing an indication that the asymmetricconfiguration is used.

In another aspect, a method that effectuates dispatch of a channelquality indicator (CQI) feedback for multicarrier systems, comprises:determining an offset or a periodicity to ensure that channel qualityindicator (CQI) reports are not conveyed in a same subframe;ascertaining whether an access terminal is power limited; and based atleast in part on the ascertaining, providing channel quality indicator(CQI) feedback on multiple carriers on the same subframe or ascertainingwhether to drop channel quality indicator (CQI) feedback on allcarriers, transmit channel quality indicator (CQI) feedback on onecarrier, or transmit channel quality indicator (CQI) feedback on asubset of carriers.

In an aspect, an apparatus that effectuates dispatch of a channelquality indicator (CQI) feedback for multicarrier systems, comprises:means for determining an offset or a periodicity to ensure that channelquality indicator (CQI) reports are not conveyed in a same subframe;means for ascertaining whether an access terminal is power limited; andmeans for providing, based at least in part on the ascertaining, channelquality indicator (CQI) feedback on multiple carriers on the samesubframe or ascertaining whether to drop channel quality indicator (CQI)feedback on all carriers, transmit channel quality indicator (CQI)feedback on one carrier, or transmit channel quality indicator (CQI)feedback on a subset of carriers.

In still another aspect, an apparatus that effectuates dispatch of achannel quality indicator (CQI) feedback for multicarrier systems,comprises: at least one processor configured to determine an offset or aperiodicity to ensure that channel quality indicator (CQI) reports arenot conveyed in a same subframe, to ascertain whether an access terminalis power limited, and to provide, based at least in part on theascertaining, channel quality indicator (CQI) feedback on multiplecarriers on the same subframe or ascertaining whether to drop channelquality indicator (CQI) feedback on all carriers, transmit channelquality indicator (CQI) feedback on one carrier, or transmit channelquality indicator (CQI) feedback on a subset of carriers.

In an aspect, a method that effectuates dissemination of channel qualityindicator (CQI) feedback for multicarrier systems, comprises: analyzingtransmission modes of downlink (DL) carriers and identifying carriersthat can be grouped; conveying configuration parameters for CQI feedbackfor each group, and carriers that belong to respective group(s); cyclingover the CQI feedbacks of the carriers from each group; and groupingchannel quality indicator (CQI) feedback based at least in part on atransmission mode associated with a corresponding downlink (DL) carrier;and based at least in part on a rank indicator collision, widebandchannel quality indicator or subband channel quality indicator (CQI)feedback on a same carrier, dropping channel quality indicator (CQI)feedback.

In another aspect, a wireless communications apparatus, comprises: aprocessor configured to: analyze transmission modes of downlink (DL)carriers and identifying carriers that can be grouped; conveyconfiguration parameters for CQI feedback for each group, and carriersthat belong to respective group(s); cycle over the CQI feedbacks of thecarriers from each group; group channel quality indicator (CQI) feedbackbased at least in part on a transmission mode associated with acorresponding downlink (DL) carrier; and drop channel quality indicator(CQI) feedback based at least in part on a rank indicator collision,wideband channel quality or subband channel quality indicator (CQI)feedback on a same carrier.

In another aspect, a wireless communications apparatus that effectuatesdissemination of channel quality indicator (CQI) feedback formulticarrier systems, comprises: means for analyzing transmission modesof downlink (DL) carriers and identifying carriers that can be grouped;means for conveying configuration parameters for CQI feedback for eachgroup, and carriers that belong to respective group(s); means forcycling over the CQI feedbacks of the carriers from each group; meansfor grouping channel quality indicator (CQI) feedback based at least inpart on a transmission mode associated with a corresponding downlink(DL) carrier; and means for dropping channel quality indicator (CQI)feedback based at least in part on a rank indicator collision, widebandchannel quality or subband channel quality indicator (CQI) feedback on asame carrier.

To the accomplishment of the foregoing and related ends, one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspectsand are indicative of but a few of the various ways in which theprinciples of the aspects may be employed. Other advantages and novelfeatures will become apparent from the following detailed descriptionwhen considered in conjunction with the drawings and the disclosedaspects are intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, nature, and advantages of the present disclosure willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout and wherein:

FIG. 1 illustrates a multiple access wireless communication systemaccording to one embodiment;

FIG. 2 illustrates a block diagram of a communication system;

FIG. 3A illustrates a multicarrier system that is symmetricallyconfigured;

FIG. 3B illustrates a multicarrier system that is asymmetricallyconfigured;

FIG. 4 illustrates an example system that provides channel qualityindicator (CQI) feedback for multicarrier systems;

FIG. 5 illustrates a methodology that dispatches channel qualityindicator (CQI) feedback for multicarrier systems in accordance with anaspect of the claimed subject matter;

FIG. 6 illustrates a methodology that dispatches channel qualityindicator (CQI) feedback for multicarrier systems in accordance with anaspect of the claimed subject matter;

FIG. 7 illustrates a methodology that can be utilized to provide channelquality indicator (CQI) feedback for multicarrier systems in an LTEbased wireless communication environment; and

FIG. 8 illustrates a methodology that dispatches channel qualityindicator (CQI) feedback for multicarrier systems in accordance with anaspect of the claimed subject matter.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that the variousaspects may be practiced without these specific details. In otherinstances, well-known structures and devices are shown in block diagramform in order to facilitate describing these aspects.

As used in this application, the terms “component”, “module”, “system”,and the like are intended to refer to a computer-related entity, eitherhardware, a combination of hardware and software, software, or softwarein execution. For example, a component may be, but is not limited tobeing, a process running on a processor, a processor, an object, anexecutable, a thread of execution, a program, and/or a computer. By wayof illustration, both an application running on a server and the servercan be a component. One or more components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers. In addition,these components can execute from various computer readable media havingvarious data structures stored thereon. The components may communicateby way of local and/or remote processes such as in accordance with asignal having one or more data packets (e.g., data from one componentinteracting with another component in a local system, distributedsystem, and/or across a network such as the Internet with other systemsby way of the signal).

Furthermore, various aspects are described herein in connection with amobile device. A mobile device can also be called, and may contain someor all of the functionality of a system, subscriber unit, subscriberstation, mobile station, mobile, wireless terminal, node, device, remotestation, remote terminal, access terminal, user terminal, terminal,wireless communication device, wireless communication apparatus, useragent, user device, or user equipment (UE). A mobile device can be acellular telephone, a cordless telephone, a Session Initiation Protocol(SIP) phone, a smart phone, a wireless local loop (WLL) station, apersonal digital assistant (PDA), a laptop, a handheld communicationdevice, a handheld computing device, a satellite radio, a wireless modemcard and/or another processing device for communicating over a wirelesssystem. Moreover, various aspects are described herein in connectionwith a base station. A base station can be utilized for communicatingwith wireless terminal(s) and can also be called, and may contain someor all of the functionality of, an access point, node, Node B, e-NodeB,e-NB, or some other network entity.

Various aspects or features will be presented in terms of systems thatmay include a number of devices, components, modules, and the like. Itis to be understood and appreciated that the various systems may includeadditional devices, components, modules, etc. and/or may not include allof the devices, components, modules etc. discussed in connection withthe figures. A combination of these approaches may also be used.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

Additionally, the one or more versions may be implemented as a method,apparatus, or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedaspects. The term “article of manufacture” (or alternatively, “computerprogram product”) as used herein is intended to encompass a computerprogram accessible from any computer-readable device, carrier, or media.For example, computer readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips. . . ), optical disks (e.g., compact disk (CD), digital versatile disk(DVD) . . . ), smart cards, and flash memory devices (e.g., card,stick). Additionally it should be appreciated that a carrier wave can beemployed to carry computer-readable electronic data such as those usedin transmitting and receiving electronic mail or in accessing a networksuch as the Internet or a local area network (LAN). Of course, thoseskilled in the art will recognize many modifications may be made to thisconfiguration without departing from the scope of the disclosed aspects.

FIG. 2 is a block diagram of an embodiment of a transmitter system 210(also known as the access point, base station and eNodeB) and a receiversystem 250 (also known as access terminal and user equipment) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In an embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides NT modulationsymbol streams to NT transmitters (TMTR) 222 a through 222 t. In certainembodiments, TX MIMO processor 220 applies beamforming weights to thesymbols of the data streams and to the antenna from which the symbol isbeing transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide NT “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

FIG. 3A illustrates a multicarrier system 300 with symmetricconfiguration, which includes downlink carriers (DL CL1 and DL CL2) 306and 310 and uplink carriers (UL CL1 and UL CL2) 308 and 312. Thesecarriers are used to exchange information between base station 302 andaccess terminal 304. Base station 302 and access terminal 304 correspondto base station 100 and access terminal 116 shown in FIG. 1. The system300 is symmetric in the that the number of downlink carriers 306 and 310are equal to the number of uplink carriers 308 and 312 and that downlinkcarrier 306 is paired with uplink carrier 308 and downlink carrier 310is paired with uplink carrier 312. Although only two downlink and twouplink carriers are shown, the system 300 can be configured to includeany suitable number of downlink and uplink carriers.

FIG. 3B illustrates multicarrier system 350 with asymmetricconfiguration, which includes downlink carriers (DL CL1, DL CL2 and DLCL3) 356, 358 and 360 and uplink carriers (UL CL1 and UL CL2) 362 and364. These carriers are used to exchange information between basestation 302 and access terminal 304. The system is asymmetric in thatthe number of downlink carriers 356, 358 and 360 are equal to the numberof uplink carriers 362 and 364. In an asymmetric system configuration,the number of downlink carriers is not equal to the number of uplinkcarrier and the downlink carriers are not necessarily paired with uplinkcarriers. In an aspect, one or more downlink carriers are be paired withonly one uplink carrier (also referred to as uplink anchor carrier shownas darkened uplink carrier 362). Although only three downlink and twouplink carriers are shown, the system 350 can be configured to includeany suitable number of downlink and uplink carriers.

In an aspect, for the multicarrier system asymmetrically configured, oneor more downlink carriers and one or more uplink carriers communicateinformation between base station 302 and access terminal 304. At varioustimes during operation of the system 350, the access terminal 304generates channel state information reports for each of the downlinkcarriers. The scheduling regarding when reports are to be provided ortransmitted to the base station 302 can be system specific or basestation specific. The reports generally include channel stateinformation, comprising channel quality indicator (CQI) feedbackregarding each downlink carrier. The base station can employ thisinformation for scheduling purposes. In an aspect, the access terminal304 uses one uplink carrier (referred to as the anchor carrier) toprovide CQI feedback for each downlink carrier used by the system. Theselection of which uplink carrier to utilize (for example, UL C1 or ULC2 of FIG. 3) may be static, semi-static or dynamic based on the systemconfiguration. This decision may be based on various factors, such assystem implementation, channel conditions, loading information orinterference levels of uplink carriers. For semi-static and dynamicconfigurations, the anchor carrier may be selected by signaling, by thebase station 302, to access terminal 304 or during a call setup orinitial acquisition. Which uplink carrier to use may be userequipment-specific (e.g., access terminal capabilities) orsystem-specific (e.g., preselected by the system). In addition, itshould be noted without limitation or loss of generality that it ispossible to use additional uplink carriers to provide CQI feedback ofone or more downlink carriers. Note that in the asymmetricconfiguration, the uplink carriers need not be paired with the downlinkcarriers.

FIG. 4 illustrates a system 400 that provides channel quality indicator(CQI) feedback for multicarrier systems that includes access point orbase station 402 which can be in continuous and/or operative, orsporadic and/or intermittent communication with access terminal or userequipment 404. The base station 402 and access terminal 404 respectivelycorrespond to the base station 302 and access terminal 304 shown inFIGS. 3A and 3B. In accordance with various aspects of the claimedsubject matter set forth herein, access terminal 404 can provide ortransmit to the base station 402 channel quality indicator (CQI)feedback for the downlink (DL) carriers (for example 356, 358 or 360illustrated in FIG. 3B). According to an aspect, the access terminal404can determine channel state information (including CQI information)of each downlink carrier and use a designated or anchor uplink (UL)carrier (for example 362 illustrated in FIG. 3B) to provide the channelstate information of the all the downlink carriers. The anchor carrieris not necessarily paired with any of the multiple downlink (DL)carriers for which channel quality indicator (CQI) feedback is beingconveyed. Transmitting channel quality indicator (CQI) feedback on adesignated or anchor uplink (UL) carrier that is not necessarily pairedwith the multiple downlink (DL) carriers for which channel qualityindicator (CQI) feedback is being conveyed typically corresponds to amany-to-one downlink/uplink (DL/UP) mapping (e.g., asymmetric carrierconfiguration). Whereas transmitting the channel quality indicator (CQI)feedback on corresponding paired uplink (UL) carriers (e.g., paired withdownlink (DL) carriers) can generally be perceived as being a one-to-one(e.g., symmetric carrier configuration).

In order to distinguish between the asymmetric and symmetricconfiguration alternatives, access terminal 404 can incorporate a flagto be used to indicate whether channel quality indicator (CQI) feedbackis being sent using an anchor scheme or a non-paired scheme. The anchorscheme comprises employing a designated or anchor uplink (UL) carrierthat is not necessarily paired with the multiple downlink (DL) carriersfor which channel quality indicator (CQI) feedback is being conveyed.For the paired scheme, the channel quality indicator (CQI) feedback isdispatched using correspondingly paired uplink (UL) carriers (e.g.,paired with downlink (DL) carriers). The flag so generated by accessterminal 404 can, for example, be conveyed on the system information(common) or by radio resource control (RRC) signaling (per accessterminal or user equipment (UE)). It should be noted without limitationor loss of generality that the flag can be applied to long termevolution advanced (LTE-A) access terminals or user equipment (UE) butcan be transparent to legacy access terminals or user equipment sincelegacy access terminals or user equipment typically send downlink (DL)channel quality indicator (CQI) feedback on the paired uplink (UL). Itshould be also noted that base station 402 may request the accessterminal, during a call setup or initial acquisition, to designate whichalternative (asymmetric—designate the anchor carrier orsymmetric—pairing) to employ.

Accordingly and in view of the foregoing, access terminal 404 caninclude symmetric carrier component 406 that can be utilized in caseswhere channel quality indicator (CQI) feedback is being dispatched usingcorrespondingly paired uplink (UL) carriers. In accordance with thisaspect of the claimed subject matter, symmetric carrier component 406,in order to achieve an independent channel quality indicator (CQI)configuration per carrier, preserve single carrier properties, andfurther to ensure that reports do not occur in the same subframe or atthe very least to minimize collisions, can monitor the offset and/orperiodicity of the carrier. Moreover, symmetric carrier component 406can also ascertain whether or not access terminal 404 is power limited.A determination by symmetric carrier component 406 that access terminal404 is not power limited can indicate that channel quality indicator(CQI) feedback can be conveyed on multiple carriers in the same subframe(NxSC-FDMA). Whereas a determination that access terminal 404 is powerlimited can provide indication to symmetric carrier component 406 thatchannel quality indicator (CQI) feedback needs to be dropped from allcarriers, transmitted on one carrier, or dispatched on a subset ofcarriers.

Access terminal 404 can also include asymmetric carrier component 408that can be employed in instances where a designated or anchor uplink(UL) carrier that is not necessarily paired with the multiple downlink(DL) carriers is being utilized to convey channel quality indicator(CQI) feedback for the downlink carriers. While there can be a number ofcontingencies that arise where the designated or anchor uplink (UL)carrier is not necessarily paired with one or more of the multipledownlink (DL) carriers, two in particular need to be addressed byasymmetric carrier component 408. Asymmetric carrier component 408 needsto address situations where more than one downlink (DL) carrier ispaired with one uplink (UL) carrier, and further asymmetric carriercomponent 408 needs to address situations where more than one uplink(UL) carrier is paired with one downlink (DL) carrier.

Where more than one downlink (DL) carrier is paired with one uplink (UL)carrier, asymmetric carrier component 408 can cycle through the channelquality indicator (CQI) feedback for all corresponding downlink (DL)carriers. It should be noted, without limitation or loss of generality,that different carrier channel quality indicator (CQI) feedback can beconfigured differently, in which case upper layer configuration needs tobe available for each carrier. Further, it should also be noted that thesame channel quality indicator (CQI) configuration typically requiresone set of configuration parameters from upper layers, and that channelquality indicator (CQI) feedback can be grouped depending ontransmission mode (e.g., single input multiple output (SIMO), multipleinput multiple output (MIMO), . . . ) on the corresponding carrierswherein the same channel quality indicator (CQI) configuration within agroup can be applied.

Additionally, asymmetric carrier component 408, in the case of rankindicator (RI) collisions and/or wideband CQI/subband channel qualityindicator (CQI) feedback on the same carrier, can drop the channelquality indicator (CQI) feedback.

It should be appreciated, once again without limitation or loss ofgenerality, that there need not be a change in physical uplink controlchannel (PUCCH) channel resources for channel quality indicator (CQI)feedback. Thus, where channel quality indicator (CQI) feedback isprovided in multiple input multiple output (MIMO) mode at most 11 bitscan be utilized. Whereas when channel quality indicator (CQI) feedbackis dispatched in single input multiple output (SIMO) mode the format canbe expanded to occupy 11 bits. These 11 bits may be used to enhance thescheduling of the CQI feedback reports. This may be accomplished byaccess terminal 404 providing CQI feedback of the scheduled downlinkcarrier along with information about which downlink carrier has the bestCQI. In an aspect, for each reporting instance the report can employ 4bits for the channel quality indicator (CQI) feedback of the appropriatecarrier (e.g., according to the cycling rule), 4 bits for the channelquality indicator (CQI) of the best channel quality indicator carrier,and 3 bits for the index of the carrier. Additionally, it is possible toinclude 2 bits for the subband index of the best subband channel qualityindicator (CQI) of the best CQI carrier. It is possible that accessterminal 404 may also provide information about downlink carrier withthe worst CQI. It should be noted in relation to sending channel qualityindicator (CQI) feedback in single input multiple output (SIMO) mode,that overhead can be decreased because the frequency of the channelquality indicator (CQI) reporting can be decreased due to the additionalreporting of the best carrier channel quality indicator (CQI) everyreporting period.

According to an aspect, the asymmetric carrier component 408, for thewideband report per carrier, the CQI may include guard bands in case ofcontiguous carriers. If the carriers are not contiguous, then the CQIfeedback will not cover the guard band portion.

According to another aspect, where more than one uplink (UL) carrier ispaired with one downlink (DL) carrier, asymmetric carrier component 408can utilize a strategy similar to that utilized by symmetric carriercomponent 406 where some uplink (UL) carriers may not be configured tocarry channel quality indicator (CQI) feedback for some user equipment.

According to yet another aspect, the asymmetrical carrier component 408,like the symmetric carrier component 406, can ascertain whether or notaccess terminal 404 is power limited. Where asymmetrical carriercomponent 408 ascertains that access terminal 404 is power limited itcan be indication that channel quality indicator (CQI) feedback needs tobe dropped on all carriers, transmitted on one carrier, or dispatched ona subset of carriers.

According to an aspect, an aperiodic reporting component 410 is utilizedto provide aperiodic reporting of reports. A periodic reporting occursbased on pre-determined period and the physical uplink control channel(PUCCH) is used to provide or transmit the reports to base station,whereas, the aperiodic reporting may be scheduled any time. Also, theaperiodic reports are dispatched via physical uplink shared channel(PUSCH). Where a physical uplink shared channel (PUSCH) is employed tosend an aperiodic report, the report can include additional subbandchannel quality indicator (CQI) and subband precoding matrix indicator(PMI) information for each carrier. Accordingly, in order to effectuatethis aspect of the claim matter, aperiodic reporting component 410 canpoll for aperiodic requests in the uplink (UL) assignment which canrefer to the channel quality indicator (CQI), precoding matrix indicator(PMI), or rank indicator (RI) report for the downlink (DL) carriers thatthe uplink (UL) is configured to send feedback for, or all configureddownlink (DL) carriers. An additional bit in the uplink (UL) assignmentcan be employed to provide this information dynamically or radioresource control signaling can configure the default operation.

Referring to FIGS. 5-8, methodologies relating to providing channelquality indicator (CQI) feedback for multicarrier systems in an LTEbased wireless communication environment are illustrated. While, forpurposes of simplicity of explanation, the methodologies are shown anddescribed as a series of acts, it is to be understood and appreciatedthat the methodologies are not limited by the order of acts, as someacts can, in accordance with one or more embodiments, occur in differentorders and/or concurrently with other acts from that shown and describedherein. For example, those skilled in the art will understand andappreciate that a methodology could alternatively be represented as aseries of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts can be required to implement amethodology in accordance with one or more embodiments.

With reference to FIG. 5, illustrated is a methodology 500 that provideschannel quality indicator (CQI) feedback for multicarrier systems inaccordance with an aspect of the claimed subject matter. As depicted,methodology 500 can commence at 502 where a determination can be maderegarding whether the anchor carrier scheme is used to provide the CQIfor the downlink carrier. At 504, if determined that the anchor carrierscheme is used, then set a flag or other indication to indicate that adesignated carrier is used to provide CQI feedback for the downlinkcarriers. The anchor carrier scheme can be multicarrier system having anasymmetric configuration, wherein the designated or anchor uplinkcarrier is used to provide CQI and the designated or anchor carrier isnot paired with the downlink carriers. At 506, one of the uplinkcarriers is designated as the anchor carrier. This determination can bedynamic or semi-static base on various factors, for example based onpower of the access terminal. At 508, after cycling through all thedownlink carriers to collect the CQI feedback, transmit the CQI feedbackof one or more downlink carrier using the designated carrier.

With reference to FIG. 6, illustrated is a methodology 600 that provideschannel quality indicator (CQI) feedback for multicarrier systems inaccordance with an aspect of the claimed subject matter. As depicted,methodology 600 can commence at 602 where a determination can be maderegarding offset and periodicity to ensure that reports are not conveyedin the same subframe or to at least mitigate collisions. At 604 adetermination can be made regarding whether or not user equipment oraccess terminals are power limited. If it is determined at 604 that userequipment or access terminals are not power limited, methodology 600 canproceed to 606 where channel quality indicator (CQI) feedback can beprovided on multiple carrier in the same subframe. On the other hand, ifit is ascertained at 604 that user equipment or access terminals arepower limited, the methodology 600 proceeds to 608 whereupon adetermination can be made as to whether to drop channel qualityindicator (CQI) feedback on all carriers, transmit channel qualityindicator (CQI) feedback on one carrier, or disseminate channel qualityindicator (CQI) feedback on a subset of carriers.

With reference to FIG. 7, illustrated is a further methodology 700 thatcan be utilized to provide channel quality indicator (CQI) feedback formulticarrier systems in accordance with an aspect of the claimed subjectmatter. Methodology 700 can cycle through channel quality indicator(CQI) feedback of all corresponding downlink (DL) carriers at 702. At704, the methodology can ascertain whether or not channel qualityindicator (CQI) feedback on different carriers are configureddifferently in which case upper layer configuration needs to beavailable for each carrier. At 706, a determination can be made as towhether or not channel quality indicator (CQI) feedback configuration issimilar, in which case only one set of configuration parameters fromupper layers is necessary. At 708, channel quality indicator (CQI)feedback can be grouped depending on the transmission mode (e.g., singleinput multiple output, multiple input multiple output, . . . ) on thecorresponding carriers. Further, at 710 channel quality indicator (CQI)feedback can be dropped in the case of collision of rank indicator (RI)and wideband channel quality indicator (CQI)/subband channel qualityindicator (CQI) feedback on the same carrier.

With reference to FIG. 8, illustrated is a methodology 800 that provideschannel quality indicator (CQI) feedback for multicarrier systems inaccordance with an aspect of the claimed subject matter. The methodologycommences at 802 by determining if the carriers for wideband reportingare contiguous. If at 804, it is determined that carriers arecontiguous, then at 808 the entire carrier including the guard bandportion is used to measure the CQI. Otherwise, at 810 the CQI ismeasured without using the guard band portion.

For a multiple-access system (e.g., FDMA, OFDMA, CDMA, TDMA, and thelike), multiple terminals can transmit concurrently on the uplink Forsuch a system, the pilot subbands may be shared among differentterminals. The channel estimation techniques may be used in cases wherethe pilot subbands for each terminal span the entire operating band(possibly except for the band edges). Such a pilot subband structurewould be desirable to obtain frequency diversity for each terminal. Thetechniques described herein may be implemented by various means. Forexample, these techniques may be implemented in hardware, software, or acombination thereof. For a hardware implementation, the processing unitsused for channel estimation may be implemented within one or moreapplication specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, micro-controllers, microprocessors,other electronic units designed to perform the functions describedherein, or a combination thereof. With software, implementation can bethrough modules (e.g., procedures, functions, and so on) that performthe functions described herein. The software codes may be stored inmemory unit and executed by processors.

It is to be understood that the aspects described herein may beimplemented by hardware, software, firmware or any combination thereof.When implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The various illustrative logics, logical blocks, modules, and circuitsdescribed in connection with the aspects disclosed herein may beimplemented or performed with a general purpose processor, a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a field programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but, in the alternative, the processor may be any conventionalprocessor, controller, microcontroller, or state machine. A processormay also be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. Additionally, at least oneprocessor may comprise one or more modules operable to perform one ormore of the steps and/or actions described above.

For a software implementation, the techniques described herein may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The software codes may be storedin memory units and executed by processors. The memory unit may beimplemented within the processor or external to the processor, in whichcase it can be communicatively coupled to the processor through variousmeans as is known in the art. Further, at least one processor mayinclude one or more modules operable to perform the functions describedherein.

The techniques described herein may be used for various wirelesscommunication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and othersystems. The terms “system” and “network” are often usedinterchangeably. A CDMA system may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includesWideband-CDMA (W-CDMA) and other variants of CDMA. Further, CDMA2000covers IS-2000, IS-95 and IS-856 standards. A TDMA system may implementa radio technology such as Global System for Mobile Communications(GSM). An OFDMA system may implement a radio technology such as EvolvedUTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA and E-UTRA are partof Universal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) is a release of UMTS that uses E-UTRA, which employsOFDMA on the downlink and SC-FDMA on the uplink UTRA, E-UTRA, UMTS, LTEand GSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). Additionally, CDMA2000 and UMBare described in documents from an organization named “3rd GenerationPartnership Project 2” (3GPP2). Further, such wireless communicationsystems may additionally include peer-to-peer (e.g., mobile-to-mobile)ad hoc network systems often using unpaired unlicensed spectrums, 802.xxwireless LAN, BLUETOOTH and any other short- or long-range, wirelesscommunication techniques.

Moreover, various aspects or features described herein may beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. The term “article ofmanufacture” as used herein is intended to encompass a computer programaccessible from any computer-readable device, carrier, or media. Forexample, computer-readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips,etc.), optical disks (e.g., compact disk (CD), digital versatile disk(DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card,stick, key drive, etc.). Additionally, various storage media describedherein can represent one or more devices and/or other machine-readablemedia for storing information. The term “machine-readable medium” caninclude, without being limited to, wireless channels and various othermedia capable of storing, containing, and/or carrying instruction(s)and/or data. Additionally, a computer program product may include acomputer readable medium having one or more instructions or codesoperable to cause a computer to perform the functions described herein.

Further, the steps and/or actions of a method or algorithm described inconnection with the aspects disclosed herein may be embodied directly inhardware, in a software module executed by a processor, or in acombination of the two. A software module may reside in RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of storage mediumknown in the art. An exemplary storage medium may be coupled to theprocessor, such that the processor can read information from, and writeinformation to, the storage medium. In the alternative, the storagemedium may be integral to the processor. Further, in some aspects, theprocessor and the storage medium may reside in an ASIC. Additionally,the ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal. Additionally, in some aspects, the steps and/or actionsof a method or algorithm may reside as one or any combination or set ofcodes and/or instructions on a machine readable medium and/or computerreadable medium, which may be incorporated into a computer programproduct.

While the foregoing disclosure discusses illustrative aspects and/oraspects, it should be noted that various changes and modifications couldbe made herein without departing from the scope of the described aspectsand/or aspects as defined by the appended claims. Accordingly, thedescribed aspects are intended to embrace all such alterations,modifications and variations that fall within scope of the appendedclaims. Furthermore, although elements of the described aspects and/oraspects may be described or claimed in the singular, the plural iscontemplated unless limitation to the singular is explicitly stated.Additionally, all or a portion of any aspect and/or aspect may beutilized with all or a portion of any other aspect and/or aspect, unlessstated otherwise.

To the extent that the term “includes” is used in either the detaileddescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprising” as “comprising” is interpretedwhen employed as a transitional word in a claim. Furthermore, the term“or” as used in either the detailed description or the claims isintended to mean an inclusive “or” rather than an exclusive “or”. Thatis, unless specified otherwise, or clear from the context, the phrase “Xemploys A or B” is intended to mean any of the natural inclusivepermutations. That is, the phrase “X employs A or B” is satisfied by anyof the following instances: X employs A; X employs B; or X employs bothA and B. In addition, the articles “a” and “an” as used in thisapplication and the appended claims should generally be construed tomean “one or more” unless specified otherwise or clear from the contextto be directed to a singular form.

What is claimed is:
 1. (canceled)
 2. A method for wireless communicationat a user equipment (UE), the method comprising: determining respectivechannel state information reports for a plurality of downlink carriersto be conveyed on a plurality of uplink carriers in a subframe;determining whether the UE is power limited for the subframe; and basedat least in part on the determining whether the UE is power limited forthe subframe, transmitting the respective channel state informationreports on the plurality of uplink carriers in the subframe, droppingthe respective channel state information reports for the plurality ofdownlink carriers in the subframe, or transmitting the respectivechannel state information reports on a subset of the plurality of uplinkcarriers in the subframe.
 3. The method of claim 2, wherein theplurality of uplink carriers comprise corresponding paired uplinkcarriers for the plurality of downlink carriers.
 4. The method of claim2, wherein more than one of the plurality of downlink carriers is pairedwith one of the plurality of uplink carriers.
 5. The method of claim 2,wherein the respective channel state information reports are transmittedon one or more physical uplink control channels.
 6. The method of claim2, wherein the respective channel state information reports compriseperiodic reports.
 7. The method of claim 2, wherein the respectivechannel state information reports comprise respective channel qualityindicator (CQI) feedback for the plurality of downlink carriers.
 8. Themethod of claim 7, wherein the respective CQI feedback for differentdownlink carriers of the plurality of downlink carriers is configuredseparately based on corresponding upper layer CQI feedbackconfigurations for the different downlink carriers, wherein eachcorresponding upper layer CQI feedback configuration comprises a set ofconfiguration parameters for providing the CQI feedback.
 9. An apparatusfor wireless communication at a user equipment (UE), comprising: atleast one processor; a memory coupled with the processor, the memorycomprising instructions which, when executed by the at least oneprocessor, cause the apparatus to: determine respective channel stateinformation reports for a plurality of downlink carriers to be conveyedon a plurality of uplink carriers in a subframe; determine whether theUE is power limited for the subframe; and based at least in part on thedetermining whether the UE is power limited for the subframe, transmitthe respective channel state information reports on the plurality ofuplink carriers in the subframe, drop the respective channel stateinformation reports for the plurality of downlink carriers in thesubframe, or transmit the respective channel state information reportson a subset of the plurality of uplink carriers in the subframe.
 10. Theapparatus of claim 9, wherein the plurality of uplink carriers comprisecorresponding paired uplink carriers for the plurality of downlinkcarriers.
 11. The apparatus of claim 9, wherein more than one of theplurality of downlink carriers is paired with one of the plurality ofuplink carriers.
 12. The apparatus of claim 9, wherein the respectivechannel state information reports are transmitted on one or morephysical uplink control channels.
 13. The apparatus of claim 9, whereinthe respective channel state information reports comprise periodicreports.
 14. The apparatus of claim 9, wherein the respective channelstate information reports comprise respective channel quality indicator(CQI) feedback for the plurality of downlink carriers.
 15. The apparatusof claim 14, wherein the respective CQI feedback for different downlinkcarriers of the plurality of downlink carriers is configured separatelybased on corresponding upper layer CQI feedback configurations for thedifferent downlink carriers, wherein each corresponding upper layer CQIfeedback configuration comprises a set of configuration parameters forproviding the CQI feedback.
 16. An apparatus for wireless communicationat a user equipment (UE), comprising: means for determining respectivechannel state information reports for a plurality of downlink carriersto be conveyed on a plurality of uplink carriers in a subframe; meansfor determining whether the UE is power limited for the subframe; andmeans for transmitting the respective channel state information reportsfor the plurality of downlink carriers in the subframe, wherein themeans for transmitting, based at least in part on whether the UE ispower limited for the subframe, transmits the respective channel stateinformation reports on the plurality of uplink carriers in the subframe,drops the respective channel state information reports for the pluralityof downlink carriers in the subframe, or transmits the respectivechannel state information reports on a subset of the plurality of uplinkcarriers in the subframe.
 17. The apparatus of claim 16, wherein theplurality of uplink carriers comprise corresponding paired uplinkcarriers for the plurality of downlink carriers.
 18. The apparatus ofclaim 16, wherein more than one of the plurality of downlink carriers ispaired with one of the plurality of uplink carriers.
 19. The apparatusof claim 16, wherein the respective channel state information reportsare transmitted on one or more physical uplink control channels.
 20. Theapparatus of claim 16, wherein the respective channel state informationreports comprise periodic reports.
 21. The apparatus of claim 16,wherein the respective channel state information reports compriserespective channel quality indicator (CQI) feedback for the plurality ofdownlink carriers.
 22. The apparatus of claim 21, wherein the respectiveCQI feedback for different downlink carriers of the plurality ofdownlink carriers is configured separately based on corresponding upperlayer CQI feedback configurations for the different downlink carriers,wherein each corresponding upper layer CQI feedback configurationcomprises a set of configuration parameters for providing the CQIfeedback.
 23. A non-transitory computer-readable medium for wirelesscommunication at a user equipment (UE), the non-transitorycomputer-readable medium comprising code which, when executed by atleast one processor, causes the UE to: determine respective channelstate information reports for a plurality of downlink carriers to beconveyed on a plurality of uplink carriers in a subframe; determinewhether the UE is power limited for the subframe; and based at least inpart on the determining whether the UE is power limited for thesubframe, transmit the respective channel state information reports onthe plurality of uplink carriers in the subframe, drop the respectivechannel state information reports for the plurality of downlink carriersin the subframe, or transmit the respective channel state informationreports on a subset of the plurality of uplink carriers in the subframe.